Destructor milling mechanism



Aug. 27, 1968 J. E. ocoNNoR ETAL 3,398,901

DESTRUCTOR MILLING MECHANISM Filed Feb. 14, 1966 5 Sheets-Sheet 1 as TAug. 27, 196s J' E UCONNQR ETAL 3,398,901

DESTRUCTOR MILLING MECHANISM 5 Sheets-Sheet 2 Filed Feb. 14, 1966 Aug.27, 1968 Filed Feb. 14, 1966 J. E. OCONNOR ETAL DESTRUCTOR MILLINGMECHANISM 5 Sheets-Sheet 5 ug. 27, 1968 1 E O'CQNNQR ETAL DESTRUCTORMILLING MECHAN I SM Filed Feb. 14, 1966 5 Sheets-Sheet 4.

Aug. 27, 1968 J. E. OCONNOR ETAL DESTRUCTOR MILLING MECHANI SM FiledFeb. 14, 1966 5 Sheng-sheet 5 ooo oooo ooooo /aoooo oooooo/7Z-4/oooooooo OOOOOOOO 76u44 A MAW @G5/ormai@ United States Patent O3,398,901 DESTRUCTOR MILLING MECHANISM James E. OConnor, Los Angeles,and Richard G. Page,

Inglewood, Calif., assignors to Document Disintegration, Inc., Gardena,Calif., a corporation of California Filed Feb. 14, 1966, Ser. No.527,137 7 Claims. (Cl. 2411-154) ABSTRACT F THE DISCLSURE An improveddestructor mechanism is described in the following specification forreducing documents, paper and similar fibrous materials to a uffyillegible consistency. The mill to be described is -a two-stage type,and is constructed to operate satisfactorily for destroying all types ofdocuments from heavy bound books, for example, to papers and the like.

The present invention relates generally to destructor mills, and itrelates more particularly to an improved destr-uctor mechansim fordestroying documents, paper, and the like, and for reducing the same to-a ufy illegible mass by mechanical means.

The disposition of discarded documents of a secret nature in such mannerthat the information contained therein cannot subsequently becomeavailable to rival manufacturers or enemy agents, has become a ratherserious problem in modern times. Prior United States Letters PatentsNumbers 3,189,286 and 3,192,853 relate to solutions of Iche problem.

However, the aspects of the problem to which the present invention isdirected concerns the diiculty of adequately destroying such documents,particularly heavy or bulky documents such as bound books and paperswhich are apt to clog presently available destruction apparatus; as wellas to the problem of positively reducing them to a uiy and entirelyillegible mass Those problems have become particularly critical in thesedays of defense secrecy and industrial espionage.

In general, in accordance with the present invention, such destructionis accomplished by employing an apparatus including a housing providinga pair of interconnecting juxtaposed chambers. In each of said chambersa power-driven rotor carrying rigidly mounted documentdestroying hammersis rotatably mounted, and the rotors -are so relatively disposed thatthe hammers of the respective rotors cooperate to produce an explosiveeffect upon the documents which substantially contributes to the desiredend result of the destructive operation.

A principal object of the present invention is to provide a dual-type ofmill for reducing documents to an illegible ulfy consistency, whichinvolves primary and secondary sections, constructed so that the primaryand secondary sections operate as a single component yand cannot operateeffectively independently of one another.

That is, each of the sections of the dual mill of the present inventioncomplements the other and neither could fbe operated stisfactorily as aseparate, single unit. In the embodiment to be described, both theprimary and secondary sections have the same power. However, the rotorin the secondary section is driven at a faster speed than the rotor inthe primary section. This is because the material increases in volume asit is pulverized, and the faster secondary section serves to lpull thematerial out of the primary section the less likelihood there is of atendency for the primary section to become clogged. In this manner, thesecondary section actually serves to increase the effective capacity ofthe primary section.

Patented Aug. 27, 1968 In the mill of the present invention theCrushers, or hammers, are rigidly mounted on their respective rotors inthe primary and secondary sections rather than being pivotally mountedthereon, `as is usually the case in the prior art machines. The primaryhammers have a particular shape, as illustrated herein, so as to breakup the documents in the primary section; and the secondary hammers havea different shape, as also illustrated herein, so as to drag thematerial around the secondary section until it is completely pulverized.

The machine of the present invention, in the embodiment to be described,also includes a plurality of breaker bars which extend into the primarysection, for example, through the housing. The primary hammers drive thematerial fed into the primary section against the heads of the breakerbars so as to initiate the p-ulverizing action.

However, prior to the material being driven against the heads of thebreaker bars by the primary hammers, the housing provides a chamberadjacent the inlet which serves as an open area in which the material isexposed to the action of the primary hammers without the correspondingaction of the breaker bars.

The above-mentioned open area permits the primary hammersto pulverizethe material at close range immediately upon the material entering theinlet of the mill, and before the material is actually forced againstthe breaker bars. This enables the material to be broken up to someextent 'before it reaches the heads of the breaker bars, so that thetendency for bulky or heavy material t0 jam the machine is minimized.

The primary hammers and the secondary hammers in the mechanism of thepresent invention cooperate with one another to create an explosive areafor the material. This explosive area occurs in the region between theprimary and secondary sections, where the tips of the two sets ofhammers successively pass one another in closely adjacent relationshipin their respective angular travels.

The material fed into the mill of the present invention is driven by theprimary hammers from the primary section to the secondary section. Thematerial is so driven through an opening between the two sections andalong a path such that the material is directed directly at the oncomingmaterial in the secondary section and against the oncoming tips of thesecondary hammers, The particles of material in the secondary sectionand the tips of the secondary hammers meet the particles from theprimary section in mid-air, with a relatively high force. The resultingdouble action creates the explosive area in which the particles ofmaterial are rapidly pulverized.

The action described in the preceding paragraph creates an explosivecondition. That is, the explosive condition occurs when the particles ofmaterial are driven in one direction at high speed by the primaryhammers, so as to meet in a head-on collision with the particles in thesecondary section and with the tips of the secondary hammers, which inthat particular region are coming from the opposite direction. Thisaction, of course, creates a high speed destruction condition of thematerial, so that the material is rapidly reduced to the desired utfystate.

In a constructed embodiment of the invention, and as will be described,both the primary and secondary rotors are rotated in the same direction,so as to create the condition described in the preceding paragraph. Inaddition, the secondary section is displaced down from the primarysection, so that the axes of rotation of the primary and secondaryrotors are disposed in a plane which is inclined at an angle of theorder of 30 with the horizontal. It has been found that such an angletends to produce the U maximum explosive effect in the aforesaidexplosion area.

An object of the present invention, accordingly, is to produce -a ruggedand lrelatively simple mechanism which is capable of reducing documents,and the like, to a lluffy consistency, and of achieving this rapidly andwith little tendency for the mechanism to jam, even when bulky andrelatively heavy documents are fed into the mechanism.

Other objects and advantages of the invention will become apparent froma consideration of the following description, when the description istaken in conjunction with the accompanying drawings, in which:

FIGURE 1 i-s a side elevational view of one embodiment of the improvedmil-ling mechanism of the present invention;

yFIGURE 2 is a sectional view of the mechanism taken stantially alongthe lines 3 3 of FIGURE 1;

FIGURE 3 is a plan view of the mechanism taken substantially along thelines 3 3 of FIGURE 1;

FIGURE 4 is Ian end elevational view, taken along the lines 4 4 ofFIGURE l, and with certain hatches, :rotors and other componentsremoved, so as to reveal other operating components of the mechanism;

FIGURE 5 is Aa sectional view of the' secondary section of the millingmechanism taken substantially along the line 5 5 of FIGURE 2;

FIGURE 6 is a perspective representation, of the primary rotor of themechanism;

FIGURE 7 is a perspective representation of the secondary rotor of themechanism; and

FIGURES 8 and 9 are developed views of the interior of the primarysection of the milling mechanism respectively taken substantially alongthe lines 8 8 and 9 9 of FIGURE 2.

As illustrated in the drawings, the milling mechanism of the inventionis supported, for example, on a concrete 'base 10 (FIGURE 5 and isanchored into the base by appropriate anchoring means 12.

The mechanism includes a primary mill section and a secondary millsection, designated 14 and 16 respectively in FIGURE 2. A primary rotor18 (FIGURE 6*) is mounted on la drive shaft 20 in the primary section;whereas a secondary rotor 22 is mounted on a drive shaft 24 in thesecondary section (FIGURE 7). The shaft 20, for example, is rotatablysupported in a pair of pillow blocks 28 and 30 (FIGURE 1); whereas theshaft 24 is rotatably supported in a pair of pillow 'blocks 32 and 34.The pillow blocks are mounted on an appropriate frame 36, which, asnoted above, is anchored on the concrete base 10.

The secondary section of the mill is disposed at a lower elevation, with-respect to the primary section, so that the shafts 20 and 24 lie in aplane which is inclined to the horizontal. This inclination may 'be ofthe order of 30, for example. It has been found that satisfactoryresults may be achieved with such an inclination. Although theinclination is not too critical, it has been found that with a 30inclination, the material is held in the primary section long enough sothat it can be reduced to a desired broken up form before it isintroduced to the secondary section, and the material so int-roducedenters the secondary section at the optimum angle for maximum explosiveeffect.

A motor 40 (FIGURE 1) drives the shaft 20 through a suitable flexiblecoupling 42, whereas a separate motor 44 drives the shaft 24 through asuitable flexible coupling 46. The motor 40 may, for example, be a 150horsepower, 1200 r.p.m. motor, of the 440-volt, 3-phase, 60-cycle type.The motor 44, may also be a 150 `horsepower motor, likewise of the440-volt, S-phase, 60-cycle type. However, the motor 44 is faster thanthe motor 40, operating at a speed, for example, of 1800 r.p.m. Althoughthe motor 44- is shown smaller than the motor 40 in the drawings, forreasons of clarity, actually they are of the same size in the embodimentunder consideration. The motors 40 and 44 are "bolted onto thel frame36, as best shown in FIG- URE 1.

The mill itself is made up of a pair of side plates and 52, which arelbolted t-o the frame 36. The side plates 50 and 52 are mounted in anupright, spaced and parallel relationship. The actual primary andsecondary sections 14 and 16 of the mill are formed by arcuate shapedmembers which extend across from one of the side plates to the other,and which are bolted to the side plates.

The side plates 50 and 52, and associated arcuate components define aninlet 54 through which the material is fed to the primary section of themill. A hopper 56 may be supported at the inlet 54, and a conveyor belt58 (FIG- URE 2), maybe used to transport the documents up from the floorlevel to the mouth of the hopper 56, so that the documents may bedropped into the hopper, and thence through the inlet 54 into theprimary section 14.

An exhaust duct 58 is mounted adjacent an outlet 60 in the housing, andthe outlet extends from below the secondary section 16. The pulverizedmaterial from the mill is drawn through the exhaust duct, and issubsequently disposed. Any suitable means may lbe used to draw thepulverized material through the exhaust duct, such as described in theaforesaid patents.

As shown in FIGURE 2, for example, the milling mechanism of the presentinvention is actually a dual mill, including the primary section 14 andsecondary section 16. The secondary mill section 16 is displaced downfrom the primary mill section 14 as mentioned above, and each operatesin conjunction with the other, as will be described. That is, neither ofthe mill sections is suitable for independent operations, and eachcomplements the other, so as properly to perform the desired pulverizingaction.

One of the aforesaid arcuate components which extends between the sideplates 50- and 52 is a cover 60. The cover 60 is pivoted to the frame 36on a shaft 62. A lifter eye 64 is provided at the other end of thecover. The cover is held in place by bolts, such as bolts 66 extendingthrough a flange of the cover and through the side plate 52 (FIGURE 2),and similar bolts extending through the side plate 50. When the machineis to 'be opened, these bolts are removed, and the cover may be movedback by a block and tackle, or by other suitable lifting mechanism,which is coupled to the eye 64. When the cover is opened, the interiorof the secondary section 16 is revealed.

An arcuate section 68 is bolted to the side plates 50 and 52, and asshown in FIGURE 2, this section extends between the side plates adjacentthe inlet 54. The inner surface of the section 68 is smooth, so as todefine an open area with the primary r-otor 18. The material introducedthrough the inlet 54 is initially exposed to the action of the primaryrotor, without any further fracturing action in this open area. In thismanner, the primary rotor is able to break up the incoming material t0some extent as -a preliminary measure, so as to minimize the tendencyfor 'bulky or heavy material to jam the mechanlsm.

A second arcuate section 70 is 'bolted to the side plates 50 and 52adjacent the section 68, and this latter section likewise extends fromone of the side plates to the other. It will be appreciated that thesections 68 and 70, and other arcuate sections to be described, serve todefine the primary section 14 and the secondary section 16 of themechanism.

A plurality of short breaker bars 72 extend through the arcuate section70, so that the heads of the bars are disposed inside the primarysection 14. These bars are bolted in place, as shown, and are formed,for example, of case hardened steel, with additional hardening beingprovided for their heads. The breaker -bars 72 are disposed in apattern, such as shown by the developed view of FIG- URE 8.

It will be appreciated that after the material fed into the primarysection 14 has undergone a preliminary breaking up in the aforesaid openarea defined by the arcuate Section 68, the material is then drivenagainst the heads of the 'breaker bars 72 by the primary rotor 18, so asto initiate the pulverizing action of the mill.

A further arcuate section 76 extends between the side plates and 52, andis bolted to the side plates. A further group of breaker bars 78 extendthrough the arcuate section 76, and these latter breaker bars are heldin place by appropriate nuts, as shown in FIGURE 2. The breaker bars 78may be disposed in a pattern such as shown by the developed view ofFIGURE 9.

A further arcuate section 80 is bolted to the side plates 50 and 52 andthis latter section extends between the side plates on the opposite sideof the inlet 54. A top breaker bar 82 is welded, 0r otherwise afiixed,to the arcuate section 80, and this breaker bar extends between the sideplates 50 and 52 to define the upper edge of the opening between theprimary section 14 and the secondary section 16.

Yet another arcuate section 84 is bolted to the side plates 50 and 52,and extends between the side plates. A bottom breaker bar 86 is welded,or otherwise attached, to the arcuate section 84, and this latterbreaker bar forms the lower edge of the opening between the primary andsecondary sections 14 and 16 of the mill. The breaker bars 82 and 86,likewise, may be formed of case hardened steel, or other hard material.

It will be appreciated that the arcuate sections described abovecooperate to define the primary section 14 of the dual mill, and thearcuate sections 80 and 84 additionally define a portion of thesecondary section 16 of the mill. The cover 60 also helps to define thesecondary section 16, and that section is completed by an arcuategrating 88 which extends between the side plates 50 and 52 at the bottomof the section.

As best shown in FIGURE 6, the primary rotor includes a plurality ofrigid strip-like hammer members 90 which are keyed to the shaft 20, bymeans for example, of a key 92 (FIGURE 2). The hammer elements 90 areformed, for example, of hardened steel, with additionally reinforcedcorners. These elements are spaced along the shaft 20, and rotate withthe shaft.

The secondary hammers are indicated as 96, and are best shown in FIGURE7. These latter hammers are keyed to the shaft 24 by means, for example,of a key 98 (FIGURE 2). The secondary hammers, likewise, are rigid, andmay be formed of case hardened steel and have additionally hardenededges.

As mentioned above, the rotors 18 and 22 are driven in the samedirection. Therefore, as the hammers 90 move up in the right handportion of the primary section 14, the hammers 96 move down in the lefthand portion ofthe secondary section 16.

As the material to be destroyed is introduced through the inlet 54, thehammers 90 originally break it up into realtively small pieces in theopen area defined by the arcuate section 68. The material is then drivendown against the heads of the breaker bars 72 and 78, so that it may befurther pulverized. Then the material is driven up towards the openingbetween the primary section 14 and the secondary section 16, and againstthe breaker bars 82 and 86 which define that opening, by the action ofthe primary rotor 18. An explosion area for the material occurs betweenbreaker bars 82 and 86, and where the tips of the two sets of hammers 90and 96- successively pass one another in the opposite directions.

That is, the material fed into the secondary section 16 by the primaryhammers 90 is driven directly into the path of the oncoming tips of thesecondary hammers 96. Therefore, the tips of the secondary hammers meetthe particles of material in mid-air and contact the particles with arelatively high force. This action creates a high speed destructioncondition of the material so that it is rapidly reduced to a desiredfluffy state.

The secondary hammers 96 then carry the fluffy material down against thegrating 818, and it is passed through the grating when it reaches adesired illegible fiufiy con- 6v sistency. A further grating 100 isprovided, so that the material must be reduced to a particularconsistency before it will be passed to the exhaust duct 58.

The material to be discharged from the mechanism collects in a chamber102 under the secondary section 16, and which cham-ber communicates withthe outlet 60. A hatch 104 may be provided, so as to permit inspectionof the material in the chamber 102.

As shown in FIGURE 4, suitable hatches may be provided in the side plate50 to provide access to the primary section 14 and secondary section 16,for example, for cleaning purpose.

It will be appreciated, of course, that although the mill of theinvention is shown as a permanent installation, it could just as well bemobile, as was the case of the particular embodiments shown in theaforesaid patents.

What is claimed is:

1. A milling mechanism for reducing fibrous material, such as documents,paper and the like, into a fiufiy illegible consistency including: ahousing having a first compartment constituting a primary section forthe milling mechanism and a second compartment constituting a secondarysection for the mechanism; a first rotor including a plurality ofprimary hammer elements mounted in said first compartment for rotationabout a first horizontal axis; a second rotor including a plurality ofsecondary hammer elements mounted in said secondary compartment forrotation about a second horizontal axis displaced from said first axisand parallel thereto; said housing including first components definingan arcuate wall for said first compartment having a smooth inner surfacesurrounding said first rotor, and including further components definingan arcuate wall for said second cornpartment having a smooth innersurface and surrounding said second rotor, said first components furtherdefining an inlet in the arcuate wall of said first compartment forreceiving material into said first compartment, said first componentsand said further components further defining an opening between saidfirst compartment and said second compartment, and said furthercomponents further defining an outlet in the arcuate wall of said secondcompartment; a plurality of breaker bar members extending through saidarcuate wall of said first compartment, said breaker bar members havingindividual heads disposed inside said first compartment and cooperatingwith said primary hammer element to break up the material introducedinto said first compartment through said inlet; drive means forrotatably driving said first rotor and said second rotor in the samedirection such that material passed through said opening by the tips ofsaid primary hammer elements meets oncoming particles of material insaid second compartment and the oncoming tips of said secondary hammerelements, whereby said material is rapidly pulverized to a fluffyconsistency in said second compartment; and an exhaust duet surroundingsaid outlet externally of said second comparltment for drawing thepulverized material through said out et.

2. The milling mechanism defined in claim 1 and which includes a firstbreaker bar disposed across the upper edge of the aforesaid openingbetween said first compartment and said second compartment, and a secondbreaker bar disposed across the lower edge of the aforesaid openmg.

3. The milling mechanism defined in claim 1 in which said second axis isdisplaced downwardly from said first axis so that said first and secondaxes are disposed in a plane defining an angle of the order of 30 withthe horizontal.

4. The milling mechanism defined in claim 1 in which said drive meansdrives said second rotor at a rotational speed higher than said firstrotor.

5. The milling mechanism defined in claim 1 in which said primary andsecondary hammer elements are rigidly mounted on said first and secondrotors and extend radially outwardlyfrom said rst and second axesrespectively.

6. The milling mechanism defined in claim 1 in which said breaker barmembers extending through said wall of said first compartment aredisplaced arcuately from said inlet so as to provide an open area forsaid primary hammer elements to eng-age the material introduced intosaid first compartment through said inlet prior to the engagement ofsaid material by the heads of said breaker bar mem-bers.

7. The milling mechanism defined in claim 1 and which includes a gratinghaving a predetermined hole dimension mounted over said outlet.

References Cited UNITED STATES PATENTS Sedberry 241-154 X Rosenfeld241-154 X Nicholson 241-80 West 241-154 Allen et al 241-154 X Beiter241-154 l0 WILLIAM W. DYER, JR., Primary Examiner.

F. T. YOST, Assistant Examiner.

